What is the distance from the point (1,-3,8) to the x-axis?

Question

What is the distance from the point (1,-3,8) to the x-axis? This is a calculus 3 question.

Answer 1

Distance between 2 points P1 to P2 in XYZ or 3-space is |P1P2| =

square root of [(X₂ - X₁)² + (Y₂ -Y₁)² + (Z₂-Z₁)²]

Answer 2

Drop perpendicular to the x-axis, it intersects x-axis at the point (1,0,0). The vector from the point (1,0,0) to the point (1,-3, 8) is perpendicular to the x-axis and its length gives you the distance from the point (1,-3,8) to the x-axis. The coordinates of a vector are (0,-3,8). Its length is √(0²+(-3)²+8²)=√73. This is your answer.